The man, potentially a former soldier, threatens victims with a shotgun, beats them, and restrains them with cable ties.

He has taken jewels and valuables worth in excess of £1 million ($US1.4 million).

A highly-skilled, violent thief has undertaken a string of seven high-stakes burglaries in southern England, using a sawn-off shotgun to threaten his victims.

Police across the southern counties of England said their shared intelligence indicates that a single man is behind a three-year trail of crime, which left his victims beaten, bruised, and bereft of some £1 million ($US1.4 million) in valuables.

An officer investigating the suspect described him as “someone who is confident, commanding, who knows exactly what they are doing, and who is incredibly decisive in their actions.”

The only imagery available of the man is dark CCTV footage showing him entering a property in Maidenhead, Berkshire. His clothing in the image makes him virtually unidentifiable. Police say he is white and around 6ft tall.

Briefing material provided by the police suggests that his unusual level of competence could point to a past in the armed forces, police, or a similar organisation.

Some elements of the British press dubbed the suspect “The Night Watcher” because of his apparent habit of hiding out near his targets over a series of weeks.

Detective Inspector Dee Fielding, of Surrey Police, issued the following appeal in the hope that members of the public will help officers identify the man:

“Whoever is responsible for these incidents may seem to have cash or income disproportionate to their job, they might also be travelling frequently, or away for long periods of time without explanation.

“If you are aware of someone who fits the description and profile, or someone who is behaving suspiciously – we urge you to get in touch with us immediately.”